1. Field of the Invention
The present invention relates to latches for retrievable flow control devices used in oil and gas industries, and more specifically to latches which are utilized to secure or to remove a flow control valve from a mandrel receiver at a subterranean location.
The use of various type latches for such purposes is well known in the oil and gas industries. However, many latches which are currently utilized in the field suffer from a major drawback: the locking ring, in many instances, "wedges" against the locking shoulder of a mandrel, which leads to bending and metal damage of the flow control device or the mandrel receiver, and as a result, to inability of the latching device to secure position of the valve in the mandrel receiver.
Another problem which is often encountered in the oil and gas industries is inability of a retrieval tool to retrieve a valve which is locked downhole. Under these circumstances, all pulling means are usually carried up to the surface, while the valve has only one direction which it can be moved-upward. The valve cannot be retrieved by driving it down through the mandrel and at the present time, the tubing is usually pulled to the surface so that the valve, in such emergency situations, can be retrieved. While such procedure could be acceptable for production on land, no similar benefit could be obtained at an offshore location. A drilling rig will have to be moved away from that particular location and the well will stay dormant until a next workover program is effected which can take as long as five to six years from the time the well is immobilized. This causes not only loss of some pieces of equipment, but what is more important, loss of production time.